The famous line from the poem chiselled into the pedestal of the Statue of Liberty - 'Give me your tired, your poor, your huddled masses yearning to breathe free' - has never been more poignant. A refugee crisis unprecedented in America's history is unfolding across its southern states.

Up to a million people need shelter. For now, their homes are sports stadia in Texas, college dormitories in Mississippi, churches, schools, hotels, community centres and private homes.

But with the draining of New Orleans expected to take up to nine months, and hundreds of thousands of homes destroyed, more permanent solutions must be found - and quickly.

'The scale of this disaster is so large that it is an entirely new challenge for emergency planners, and they can't do it alone,' said Rutherford H Platt, a professor of geography at the University of Massachusetts.

States neighbouring the worst-hit areas of Louisiana and Mississippi have been quick to respond. In Texas, Governor Rick Perry's administration has identified about 18,000 vacant apartments that could be used to house families in the longer term.

The state has already taken in more than 75,000 evacuees in 56 short-term shelters, and has at least that number again staying in hotels. With thousands more 'temporary Texans' arriving daily, officials say they need all the help they can get from anyone with accommodation to spare.

Other states are hoping to convert former schools or other disused buildings into semi-permanent accommodation, but, with so many people looking for shelter, it is unlikely that everyone who has been displaced will ever be under a proper roof.

After Hurricane Andrew ravaged south Florida in 1992, tent cities were erected for the tens of thousands of homeless victims by the Federal Emergency Management Agency (Fema), an exercise that will be repeated on a much wider scale now.

The job of finding locations falls largely to the Army Corps of Engineers. Commanding officer Lieutenant General Carl Strock said one area of green space in the dry part of New Orleans had already been identified as a possible site for a city of 50,000.

One of the biggest challenges will be providing a decent quality of life for the evacuees. Many states have said they will open up their schools to displaced children and hospitals to the sick and elderly, but many lost their jobs as well as their homes.

The cost to Fema, which will eventually provide tens of thousands of mobile homes, tents, sleeping bags, food, generators and other essentials, is expected to run to billions of dollars. Nobody will yet predict how long that commitment will have to last.